General Specifications for NRG COMPANY, INCORPORATED Rectangular Clarification Equipment Part 2 - Products 2.6 Shafts   All shafting shall be solid, cold rolled finished steel, straight and true. Shaft material shall be C1018 or C1045. All shafts shall turn in the bearings mounted on the side walls and shall extend across the full width of the tank (except for static shaft system where bearings on idler shafts are not required). Split, cast iron set collars shall be attached to the shafts with stainless steel hardware and held in place by stainless steel set screws to keep the shafts in proper alignment. Head shafts shall contain key ways with fitted keys sized to transmit the power required.